Steroid Regulation of Ion Channels

离子通道的类固醇调节

• 批准号: 6865492
• 负责人: LESLIE P HENDERSON
• 金额: $ 23.85万
• 依托单位: DARTMOUTH COLLEGE
• 依托单位国家: 美国
• 财政年份: 2001
• 资助国家: 美国
• 起止时间: 2001-04-01 至 2006-02-28
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/6865492
• 关键词: Steroid; Regulation; Ion; Channels

EXCEED THE SPACE PROVIDED. Anabolic-androgenic steroids (AAS) are synthetic derivatives of testosterone developed for hypogonadism and treatment of wasting disorders. While still invaluable therapeutic tools, illicit use of suprapharmacological doses of AAS has overshadowed their clinical use, not only with respect to elite athletes, but also a growing number of "ordinary citizens", and most disturbingly, an appreciable number of adolescents. Chronic AAS use in both human subjects and animal models is associated with marked behavioral changes; the most notable of which are in sexual/reproductive behaviors, aggression and anxiety. Neurotransmission mediated by 7-3minobutyric acid type A (GABAA) receptors in the forebrain plays a crucial role in the expression of all of these behaviors. Interestingly, positive mood symptoms, including euphoria, hypomania and decreased anxiety are also reported, either immediately after exposure or early in the course of AAS use. These effects are reminiscent of the actions of benzodiazepines, ethanol and neurosteroids, and suggest that some of the early positive behavioral manifestations in AAS use may also arise from allosteric modulation of forebrain GABAergic transmission. We have previously shown that chronic AAS treatment alters GABAA receptor expression and function in the basal forebrain in an age- and sex-specific manner. We have also shown that acute AAS administration rapidly alters GABAA receptor function via allosteric modulation and that this modulation depends upon subunit composition. In the current proposal, we will take advantage of a transgenic mouse strain to determine the role of the E subunit in how the AAS alter GABAergic transmission in gonadotropin releasing hormone (GnRH) neurons that control the hypothalamic-pituitary-gonadal axis and are therefore the key regulators of pubertal onset and reproductive maturation. We will take advantage of a specific GABAA receptor subunit knockout strain of mice to determine the role of the a subunits in regulating AAS modulation of neural circuits important for the expression of anxiety. Finally, we will assess how posttranslational modifications of the GABAA receptor regulate allosteric modulation by the AAS and if these changes vary with the age,sex and hormonal state. To these ends we will use whole cell patch clamp recording from acutely isolated brain slices coupled with single cell real time PCR; ultrafast perfusion to recombinant receptors in heterologous cells, and behavioral assessment (ethological elevated plus maze) for anxiolytic effects of the AAS. While the behavioral actions of the AAS are well documented, the underlying neural substrates for these effects are not well known. Our data will generate data important for understanding how these steroids alter neuronal function to produce effects on reproductive and mental health, and how their effects differ in men vs. women and adults vs. children who abuse them. PERFORMANCE SITE ========================================Section End===========================================

超出所提供的空间。合成代谢雄激素类固醇（AAS）是睾酮的合成衍生物，用于性腺功能减退和治疗消耗性疾病。尽管AAS仍然是非常宝贵的治疗工具，但非法使用超药理剂量的AAS已经使其临床使用黯然失色，不仅对优秀运动员，而且对越来越多的“普通公民”，最令人不安的是，对相当数量的青少年。在人类受试者和动物模型中长期使用AAS与显著的行为变化相关;其中最显著的是性/生殖行为、攻击和焦虑。前脑7- 3-氨基丁酸A型（GABAA）受体介导的神经传递在所有这些行为的表达中起着至关重要的作用。有趣的是，积极的情绪症状，包括欣快，轻躁狂和焦虑减少也报告，无论是在暴露后立即或早期的过程中使用AAS。这些作用使人联想到苯二氮卓类、乙醇和神经类固醇的作用，并表明AAS使用中的一些早期积极行为表现也可能源于前脑GABA能传递的变构调节。我们以前已经表明，慢性AAS治疗改变GABAA受体的表达和功能在基底前脑的年龄和性别特异性的方式。我们还表明，急性AAS管理迅速改变GABAA受体的功能，通过变构调制，这种调制依赖于亚基组成。在目前的建议中，我们将利用转基因小鼠品系，以确定的作用，E亚基如何AAS改变GABA能在促性腺激素释放激素（GnRH）神经元，控制下丘脑-垂体-性腺轴的传输，因此是青春期开始和生殖成熟的关键调节。我们将利用一个特定的GABAA受体亚基基因敲除小鼠品系，以确定的作用，在调节AAS调制的神经回路的焦虑的表达是重要的。最后，我们将评估GABAA受体的翻译后修饰如何通过AAS调节变构调节，以及这些变化是否随年龄、性别和激素状态而变化。为此，我们将使用急性分离的脑切片的全细胞膜片钳记录结合单细胞真实的时间PCR;异源细胞中重组受体的超快灌注，以及AAS抗焦虑作用的行为评估（行为学高架迷宫）。虽然AAS的行为作用有很好的记录，但这些作用的潜在神经基质并不为人所知。我们的数据将产生重要的数据，以了解这些类固醇如何改变神经元功能，对生殖和心理健康产生影响，以及它们的影响在男性与女性和成年人与滥用它们的儿童中有何不同。性能现场=